This application claims the priority of German patent document 199 53 701.1, filed Nov. 8, 1999, the disclosure of which is expressly incorporated by reference herein.
The present invention is directed to a method and apparatus for reducing pressure and temperature on the front of a missile at ultrasonic speed.
For 30 years, pressure and temperature have been reduced at the front of missiles at ultrasonic speed with the aid of a rod (spike or aerospike), and numerous publications have addressed this subject. One example is the Lockheed-Martin Trident missile, a long-range rocket that is fired from submarines. In a publication AIAA 95-0737, a plate-shaped mount (aerodisk) is placed on the tip of the aerospike with approximately three-times the diameter of the spike to attain the desired effect at constant spike lengths for a wide range of speed. Until now, however, it has not been possible for such missiles to fly at high ultrasonic speeds or at high Mach numbers at high angles of incidence (approximately 10xc2x0) without a very large amount of resistance and without the full ram temperature, which substantially limits the maneuverability of a missile.
One object of the invention is to create an arrangement that protects the sensitive nose of the missile from damaging pressure and temperature not only for a wide range of speed but also for high angles of incidence.
This and other objects and advantages are achieved by the method and apparatus according to the invention, which uses an aerospike with an added spherical, ellipsoid or drop-shaped mount on the front end. The separation of the fluid flow from such a body as well as its surrounding flow in general are independent of the angle of incidence, and hence to a large extent, so is its effect on the following flow around the aerospike and the flow on the front of the missile. Missiles can hence be created that are highly maneuverable at high ultrasonic speeds without high pressures and temperatures arising at the front the resistance and hence the required thrust of such a missile is strongly reduced when the invention is applied, which correspondingly increases the range and flight duration of such a missile.
Other objects, advantages and novel features of the present invention will become apparent from the following detailed description of the invention when considered in conjunction with the accompanying drawings.